Washington, January 8 Technical finesse helped Brad Pitt to play his 80-something character transform into an infant in his latest flick 'The Curious Case of Benjamin Button'.

The film, that tells the story of a man born in his 80s and who then physically grows younger, used a totally computer generated version of Pitt as Benjamin - from the neck-up.

"For all intents and purposes, we effectively created a digital puppet of Brad that Brad could operate," CBS News quoted Ed Ulbrich, executive VP of production at Los Angeles' Digital Domain, as saying.

The high-tech transformation included using 3-D computer models to record the actor's various expressions that were later aged and uploaded accordingly.

Pitt said: "You just spend the day being a jackass doing this or doing this. Trying to map all my facial expressions, muscles. We did that for a few days."

Ulbrich added: "What was important to us in this process was that the emotions that Brad carries as an actor come through Benjamin." (ANI)